The 2008 National Electrical Code (NEC) requires that swimming pool water be electrically bonded in order to place the water at the same electrical potential as ground. Conductivity between the water and ground must be maintained by a solid copper conductor not smaller than #8 AWG. Bonding is also required for various other pool components in order to reduce voltage gradients between and among the pool water and the various components.
At least 9 square inches of bonding electrode surface area must be in contact with the water according to the NEC. However, stray voltage in the ground can create a slight voltage gradient wherein the ground is at higher potential than the pool water. Under such circumstances, the bonding electrode can slowly dissolve into the water through electrolysis, and insufficient bonding electrode surface area can result.
Finding or creating a port of entry for the grounding conductor presents a challenge for pool bonding, as does placing the bonding electrode at a location where it remains in contact with the pool water under varying conditions, such as where the water level drops, during pump failure or malfunction, or where water in pool filtration and recirculation plumbing becomes displaced by air.
Accordingly, an advantageously located replaceable binding electrode that utilizes an existing port of entry for the ground conductor is needed.